Turbocompressor



DEC. 25, GR|FF|TH TURBO-COMPRESSOR Filed Oct. 5, 1942 4 Sheets-Sheet l FIG. I

jyd.

Dec. 25, 1945. A. A. GRIFFITH TURBO-COMPRESSOR Filed Oct. 5, 1942' 4 SheetsSheet 2 Inventor MM Attorney 1945. A. A. GRIFFITH 2,391,779

TURBO-COMPRESSOR Filed Oct. 5, 1942 4 Sheets-Sheet 3 a4- s+o 36 A llorney Dec. 25, 1945. GRlFFlTH 2,391,779

TURBO-COMPRESSOR Filed Oct. 5, 1942 4 Sheets-Sheet 4 FIG. 4

Attorney Patented Dec. 25, 1945 TURBOCOMPRESSOB Alan Arnold Griillth, Derby, England Application October 5, 1942, Serial No. 460,787 In Great Britain September 5, 1929 Claims. (01. 230-116) This invention relates to turbo-compressors embodying turbine driving means and comprising a plurality of independently rotatable members each of which carries turbine blades and compressor blades. It is an object or the invention to provide means for counterbalancing, by fluid pressure applied to the independently rotatable members, thrust thereon in the axial direction set up while the turbine-driven turbo-compressor is functioning.

Various arrangements or forms of construction of turbine-driven turbo-compressor embodying the present invention are illustrated by way of example in the accompanying drawings, in which:

Fig. 1 is a longitudinal halt section and half elevation of one form of radial flow turbo-compressor;

Fig. 2 is a longitudinal view, partly in section, of one form of axial flow turbo-compressor;

Fig. 3 is a longitudinal view, partly in section, of another form of axial flow turbo-compressor;

Fig. 4 is a longitudinal section on an enlarged scale of part of. a still further form of axial flow turbo-compressor.

In the case of the radial flow turbo-compressor illustrated in Fig. 1, a number of independently rotated bladed members are nested concentrically within one another. Each bladed member is made up of three rings I, 2, 3 of equal diameter to which two rows of blades 4, 5 are attached with the blades extending parallel to the common axis 6-6 or the rings. One of the two outer rinss I is attached to the turbine blades 4 of the member and the other outer ring 3 is attached to the compressor blades 5. The middle ring 2is attached to both sets of blades 4, 5. In order to provide for differential thermal expansion the central part i of the middle rin 2 may be reduced to a suitable small radial thickness, so as to form a short thin-walled cylindrical tube. Starting from the smallest and innermost member, the outer diameter of this member is made slightly less than the inner diameter of the next larger member and so on to the outermost member, so that suitable small workin clearances are provided between the radially successive element. In this form of the invention the direction of flow of the air or other'fluid undergoing compression is preferably radially inwards from the volute inlet 9 through the successive rows of compressor blades 5 to the axial outlet Ill, and the direction of flow or the expanding products of combustion or hot air is radially outwards from the axial inlet ll through the successive rows of turbine blades 4 to the volute outlet II.

The casing of the turbo-compressor is constructed in two parts l3, l4, which are bolted together and are formed with concentric bearings l6, It for the outer rings of the members to rotate in.

i1, i3 are fixed guide blades in the casing.

i6, 20 are air Jackets, 2|, 22 are air supply pipes and ducts 23, 24 lead from the jackets to the bearings l5, l6 which constitute annular stator elements in which the members rotate. The bearings are in this manner air lubricated'and thrust in the axial direction upon each bladed member is balanced by fluid pressure applied thereto.

Referring to Fig. 2, annular stator elements 30 are secured to a hollow shaft 3| carriedby end caps 32 secured to a casing 33. Between the stator elements are independently rotatable bladed members generally indicated at 34 and carrying compressor blades 35 and turbine blades 36 connected by a shrouding ring of S-section. Axial thrust on the rotatable members is balanced by compressed air supplied through the ducts 31 in the stator elements from the hollow shaft 3| which is connected to any convenient source of compressed air. Radial ducts 38 may also be Drovided in the stator elements so that a radial outward pressure is applied to each rotatable member to provide an air-lubricated bearing between it and the adjacent stator element. In operation of this apparatus successive rotatable elements will rotate relatively to one another.

In the form shown in Fig. 3 the stator elements are bladed. In this form each stator element has compressor blades I35 secured to an annulus I34 and turbine blades I36 secured to the blades l35 through a common shrouding ring of S-section and to the wall of the casing 33.

Between each pair of stator elements is mounted an independently rotatable bladed member generally indicated at 34 and having compressor blades 35 and turbine blades 36. Each member 34 is mounted on an independent shaft 340. In operation all the independently rotatable members 34 rotate in the same direction but at difierent speeds.

To balance axial thrust on the members 34, ducts 39, 40, are provided in each stator annulus I34, said ducts conveying compressed fluid from adjacent a compressor blade at points where the pressures differ to either side of the associated annulus I34, the duct 40 being arranged near the high pressure part of the associated compressor blade I. Thus each rotatable member is sub- Ject to a pressure diflerence at the two sides thereof which acts in opposition to the axial thrust thereon.

The arrangement shown in Fig. 4 differs from that shown in Fig. 3 in constructional details of the bladed elements and in that the outer blades It and Ill constitute compressor blades while the inner blades "and Ill constitute turbine blades,

fluid pressure for balancing axial thrust consel quently being obtained from the working fluid in the driving turbine instead of from the fluid undergoing compression in the turbo-compressor.

I claim:

1. A turbo-compressor comprising a casing and a plurality 01' independently rotatable members mounted therein, each of said rotatable members carrying a set of turbine blades and a set of compressor blades, and a set of ducts adapted to carry fluid under pressure to one side of each independently rotatable member to balance thrust in the axial direction.

2. A turbo-compressor, comprising a casing, annular stator elements supported therein, a plurality of independently rotatable members mounted therein between said stator elements, each of said rotatable members carrying a set of turbine blades and a set or compressor blades, and means for applying fluid pressure between each stator element and an adjacent rotatable member to balance thrust thereon in the axial direction.

3. A turbo-compressor, comprising a casing divided into compartments by bladed stator elements each oi! which has two sets of blades arranged concentrically, a rotatable member in each compartment carrying two sets of blades corresponding with the blades carried by the stator elements and co-operating with them to consti- 4o tute respectively turbine blades and compressor blades, said rotatable members being independently rotatable, and ducts in each or said stator elements leading from near a compressor blade in high and low pressure regions to the two ad- Jacent compartments whereby different fluid pressures are applied to the two sides of each rotatable member to balance thrust thereon in the axial direction.

4. A turbo-compressor embodying turbine means for driving the same, said turbo-compressor comprising a casing, annular stator elements supported therein, and a plurality of relatively rotatable members mounted therein, said relatively rotating members having a set of turbine blades and a set of compressor blades, and means for applying fluid pressure to at leastone side of at least one of said relatively rotatable members to balance end thrust thereon in the axial direction.

5. An axial flow turbo-compressor embodying turbine driving means and comprising a casing, means for admitting fluid to be compressed at one end or said casing and for removing compressed fluid from the other end of said casing, means for supplying driving fluid to one end of said casing and for exhausting said driving fluid from the other end, said fluids passing through' said casing in counterflow, a series of alternating stator elements and relatively rotatable members mounted in said casing, each element and member having a set of turbine blades and a set 01 compressor blades concentrically arranged, and means for transmitting fluid under pressure through each stator element to a surface of each of the adjacent rotatable members so that the end thrust on the rotatable members is balanced by fluid pressure difference at the two sides there- ALAN ARNOLD GRIFFITH. 

